ref: 45524679c6798b3d8b75ab03d54a53bf46912871
parent: a3e842f9c69a3ce3bcde0ab7b0cfbeead10ed80f
author: Werner Lemberg <[email protected]>
date: Wed Aug 22 06:31:05 EDT 2018
[truetype] Improve legibility of `glyf' parsing. * src/truetype/ttgload.c (ON_CURVE_POINT, X_SHORT_VECTOR, Y_SHORT_VECTOR, REPEAT_FLAG, X_POSITIVE, SAME_X, Y_POSITIVE, SAME_Y, OVERLAP_SIMPLE): New macros. (TT_Load_Simple_Glyph): Use new macros to make code more readable. Remove useless adjustment of `outline->tags' elements.
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2018-08-22 Werner Lemberg <[email protected]>
+
+ [truetype] Improve legibility of `glyf' parsing.
+
+ * src/truetype/ttgload.c (ON_CURVE_POINT, X_SHORT_VECTOR,
+ Y_SHORT_VECTOR, REPEAT_FLAG, X_POSITIVE, SAME_X, Y_POSITIVE, SAME_Y,
+ OVERLAP_SIMPLE): New macros.
+ (TT_Load_Simple_Glyph): Use new macros to make code more readable.
+ Remove useless adjustment of `outline->tags' elements.
+
2018-08-21 Werner Lemberg <[email protected]>
* src/sfnt/ttcpal.c (tt_face_load_cpal): Add missing safety check.
--- a/src/truetype/ttgload.c
+++ b/src/truetype/ttgload.c
@@ -50,6 +50,21 @@
/**************************************************************************
*
+ * Simple glyph flags.
+ */
+#define ON_CURVE_POINT 0x01 /* same value as FT_CURVE_TAG_ON */
+#define X_SHORT_VECTOR 0x02
+#define Y_SHORT_VECTOR 0x04
+#define REPEAT_FLAG 0x08
+#define X_POSITIVE 0x10 /* two meanings depending on X_SHORT_VECTOR */
+#define SAME_X 0x10
+#define Y_POSITIVE 0x20 /* two meanings depending on Y_SHORT_VECTOR */
+#define SAME_Y 0x20
+#define OVERLAP_SIMPLE 0x40 /* we ignore this value */
+
+
+ /**************************************************************************
+ *
* Composite glyph flags.
*/
#define ARGS_ARE_WORDS 0x0001
@@ -62,7 +77,7 @@
#define WE_HAVE_A_2X2 0x0080
#define WE_HAVE_INSTR 0x0100
#define USE_MY_METRICS 0x0200
-#define OVERLAP_COMPOUND 0x0400
+#define OVERLAP_COMPOUND 0x0400 /* we ignore this value */
#define SCALED_COMPONENT_OFFSET 0x0800
#define UNSCALED_COMPONENT_OFFSET 0x1000
@@ -337,7 +352,7 @@
FT_Byte *flag, *flag_limit;
FT_Byte c, count;
FT_Vector *vec, *vec_limit;
- FT_Pos x;
+ FT_Pos x, y;
FT_Short *cont, *cont_limit, prev_cont;
FT_Int xy_size = 0;
@@ -454,7 +469,7 @@
goto Invalid_Outline;
*flag++ = c = FT_NEXT_BYTE( p );
- if ( c & 8 )
+ if ( c & REPEAT_FLAG )
{if ( p + 1 > limit )
goto Invalid_Outline;
@@ -480,31 +495,29 @@
for ( ; vec < vec_limit; vec++, flag++ )
{- FT_Pos y = 0;
- FT_Byte f = *flag;
+ FT_Pos delta = 0;
+ FT_Byte f = *flag;
- if ( f & 2 )
+ if ( f & X_SHORT_VECTOR )
{if ( p + 1 > limit )
goto Invalid_Outline;
- y = (FT_Pos)FT_NEXT_BYTE( p );
- if ( ( f & 16 ) == 0 )
- y = -y;
+ delta = (FT_Pos)FT_NEXT_BYTE( p );
+ if ( !( f & X_POSITIVE ) )
+ delta = -delta;
}
- else if ( ( f & 16 ) == 0 )
+ else if ( !( f & SAME_X ) )
{if ( p + 2 > limit )
goto Invalid_Outline;
- y = (FT_Pos)FT_NEXT_SHORT( p );
+ delta = (FT_Pos)FT_NEXT_SHORT( p );
}
- x += y;
+ x += delta;
vec->x = x;
- /* the cast is for stupid compilers */
- *flag = (FT_Byte)( f & ~( 2 | 16 ) );
}
/* reading the Y coordinates */
@@ -512,35 +525,36 @@
vec = gloader->current.outline.points;
vec_limit = vec + n_points;
flag = (FT_Byte*)outline->tags;
- x = 0;
+ y = 0;
for ( ; vec < vec_limit; vec++, flag++ )
{- FT_Pos y = 0;
- FT_Byte f = *flag;
+ FT_Pos delta = 0;
+ FT_Byte f = *flag;
- if ( f & 4 )
+ if ( f & Y_SHORT_VECTOR )
{if ( p + 1 > limit )
goto Invalid_Outline;
- y = (FT_Pos)FT_NEXT_BYTE( p );
- if ( ( f & 32 ) == 0 )
- y = -y;
+ delta = (FT_Pos)FT_NEXT_BYTE( p );
+ if ( !( f & Y_POSITIVE ) )
+ delta = -delta;
}
- else if ( ( f & 32 ) == 0 )
+ else if ( !( f & SAME_Y ) )
{if ( p + 2 > limit )
goto Invalid_Outline;
- y = (FT_Pos)FT_NEXT_SHORT( p );
+ delta = (FT_Pos)FT_NEXT_SHORT( p );
}
- x += y;
- vec->y = x;
+ y += delta;
+ vec->y = y;
+
/* the cast is for stupid compilers */
- *flag = (FT_Byte)( f & FT_CURVE_TAG_ON );
+ *flag = (FT_Byte)( f & ON_CURVE_POINT );
}
outline->n_points = (FT_Short)n_points;